USQCD has developed a suite of software enabling lattice QCD computations to be peformed with high performance across a variety of architectures, including both custom facilities and commodity clusters.  This software is made up of software library modules that can be re-used by higher level applications.   The approximate organisation of the packages into layers is depicted  below (we omit here 3rd party packages or packages auxiliary to another package). Please click on the plaquettes below to find project web pages of the individual software modules, as well as to complete lattice QCD packages which use them.

Chroma CPS FUEL MILC QLUA
Inverter MDWF QOPQDP QUDA
QDP++ QDP QIO
QLA QMP QMT
Figure 1: The SciDAC Layers and the software module architecture.

The Lattice QCD science output comes from applications packages (yellow plaquettes) which provide a context in which the underlying SciDAC modules can perform their work. Level 1, Level 2, and Level 3 packages can be built independently of the applications and used in your own codes if you wish. However, please heed this warning:
 Given the number of modules and the combinatorically larger variety of possible ways to combine them, we suggest that if you are new to this game you can save yourself a lot of frustration by checking out one of the application suites.